Transcript PowerPoint - Division for Planetary Sciences

Buried Carbonates at Mars
• Infrared observations from spacecraft
orbiting Mars are used to determine the
composition of minerals on the surface
• Impacts expose material previously
buried below the surface
• Observations from the center of one
Martian crater show carbonate rocks
(containing CO3), which have been
detected only in restricted areas
elsewhere on Mars
• The most likely explanation implies the
carbonates formed in an ancient body of
water in contact with Mars’ carbon
dioxide (CO2) atmosphere
Discoveries in Planetary Science
False color image of the interior of a Martian
crater from NASA’s Mars Reconnaissance
Orbiter, showing exposed raised light-colored
regions containing carbonates
http://dps.aas.org/education/dpsdisc/
Martian Climate and Volcanism
Carbonates require liquid water and CO2
to form. The observations reveal the
end of a multi-stage process:
1
2
3
4
1. Carbonates form at the surface in the
presence of liquid water, possibly in a
denser ancient atmosphere
2. The atmosphere changed and/or
liquid surface water disappeared surface carbonates stopped forming
3. Subsequent volcanic activity buried
the carbonates, altering them
4. Impacts exposed the carbonates in
some places, including tell-tale
signatures of their alteration
Discoveries in Planetary Science
Possible stages of carbonate formation, burial, and
exposure in Martian craters. Note that other
processes, such as rivers or tectonics, are also
capable of exposing subsurface rocks.
http://dps.aas.org/education/dpsdisc/
The Big Picture
• We can find the past history of water on
a planet by looking in craters or valleys
at exposed rocks laid down over history
• The observations suggest that more
carbonates could have formed on Mars
than have been observed so far, but they
may have been buried by volcanism
• On Earth, waters where carbonates form
(like the oceans) provide ideal habitats
for life. Carbonate areas may be a good
place to look for evidence of life on Mars
• The observations of carbonates have
scientists asking how widespread they
are, how much Martian atmosphere they
trapped,and whether they preserve
evidence for life
Discoveries in Planetary Science
An environment capable of supporting liquid
water early in Martian history would have
allowed the formation and subsequent burial of
carbonates.
http://dps.aas.org/education/dpsdisc/
For More Information…
Press
•
Universe Today - 10/11/10 - “Habitable Environments Could Exist Underground on Mars”
http://www.universetoday.com/75511/habitable-environments-could-exist-underground-on-mars/
•
MSNBC.com - 10/12/10 - “Deep hotspots on ancient Mars looked habitable”
http://www.msnbc.msn.com/id/39639281/ns/technology_and_science-space/
•
JHUAPL - 12/18/08 - “Scientists Find "Missing" Mineral and New Mars Mysteries”
http://www.jhuapl.edu/newscenter/pressreleases/2008/081218.asp
Images
•
Slide 1 image courtesy NASA / JPL / U. Arizona
http://i.space.com/9306-deep-hotspots-ancient-mars-looked-habitable.html
•
Slide 3 image courtesy Ittiz
http://en.wikipedia.org/wiki/File:AncientMars.jpg
Source Articles
•
(on-campus login may be required to access journals)
Michalski and Niles, ‘Deep crustal carbonate rocks exposed by meteor impact on Mars’, Nature
Geoscience, 3, doi:10.1038/ngeo971, 2010.
http://www.nature.com/ngeo/journal/v3/n11/full/ngeo971.html
•
Ehlmann et al., ‘Orbital identification of carbonate-bearing rocks on Mars’, Science, 208,
doi:10.1126/science1164759, 2008.
http://www.sciencemag.org/content/322/5909/1828
Prepared for the Division for Planetary Sciences of the American Astronomical Society by David Brain and Nick Schneider
[email protected] - http://dps.aas.org/education/dpsdisc/ - Released 15 April, 2011
Discoveries in Planetary Science
http://dps.aas.org/education/dpsdisc/